I am not a control freak
I am when it comes to my data. And I see where you're coming from
This is what I did and it's not too hard for anyone else to repeat the process:
I've made a "man in the middle" attack to see what data is being transferred between the game and the AWS servers running the "Master Server" of IL-2 Great Battles.
I did so in order to both see how much of my data gets dumped into their "big data" pool, and in order to get a feeling of how much IL-2 Great Battles is Cheater proof.
Part one was a positive surprise, part two rather negative.
First and aforemost, all the data transfer between client and master server is TLS encrypted on the outer transport layer, and it's additionally proprietarily encrypted "inside".
The latter encryption isn't too tough, it's probably just to keep the wannabe hacking kids from getting in within a minute.
This is already the disappointment concerning cheater protection: With a little bit of skill, you can do what I did, setup your own forwarding TLS proxy to sit in the middle of the data stream and manipulate the data (which I didn't do but could have done). Probably not what you would want to happen in an online game, and unfortunately in contrast to e.g. IL-2 1946, IL-2 Great Battles has no additional protection layer like checking the game files, code contents, flight models or anything else at connection time or during the online session. You can get in, and if you know how to do a man in the middle attack and know how to decrypt/re-encrypt the proprietary inner data format, you can basically cheat as you like.
The good thing is that the data being "leaked" to the master server, at least the mandatory part of it ("offline" mode that is) really only contains your account's email addy and the password hash. Both encrypted, the hash apparently salted. Fine with me. There seems to be no other "chatter" going on between client and master server in "offline" mode apart from this login procedure.
Online mode is different.
I don't say it's good or bad.
It's the design of the game.
All is tied to your single il2sturmovik.com account, and all what you do, be it multiplayer sessions, campaigns, whatever... is synchronized to the "master" server.
Therefore, if e.g. you play an offline campaign, the client will still sync your process in the campaign every few seconds to the master server. Constant chatter. Not apparently anything "secret" inside, but of course when you have access to the master server data, you can see who was playing which campaign when and for how long, how successful it went, what players do before and afterwards, etc. pp... "glassy customer" so to say.
Again, it's the game design showing through here.
On the pro side of this, regardless where you (re)install the game, as soon as you login to your account, you're exactly where you stopped playing on another system before.
It's all in the cloud.
Comfortable, yes. Secure, not necessarily.
Cheers!
Mike